Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA.
J Orthop Res. 2013 Sep;31(9):1406-13. doi: 10.1002/jor.22388. Epub 2013 Jun 6.
Bone is typically well suited for its habitual loading environment because of its ability to adapt. Although characteristics of the mechanical loading environment predict the bone adaptive response in animals, this has not been prospectively validated in humans. Here, we describe an in vivo loading model in which women apply forces to the radius by leaning onto their hand. We characterized the strain environment imposed on the radius using cadaveric experimentation and conducted a prospective study in which 19 adult women loaded their distal radii 50 cycles/day, 3 days/week, for 28 weeks and seven additional adult women served as controls. In four cadaveric specimens, loading caused compressive principal strains of -1,695 ± 396 με with radial bending dorsally and towards the ulna. Prospective in vivo loading produced measurable improvements to bone and appeared to protect against bone loss associated with seasonal fluctuations in physical activity and sun exposure. Experimental subjects had significant gains to bone volume (BV) and moments of inertia, while, control subjects had significant losses in BMC and moments of inertia. The loading model is thus suitable as a model system for exploring bone adaptation in humans, and may eventually be clinically useful for strengthening the radius of women.
骨骼通常非常适合其习惯性的加载环境，因为它具有适应能力。尽管机械加载环境的特征可以预测动物的骨骼适应性反应，但这在人类中尚未得到前瞻性验证。在这里，我们描述了一种体内加载模型，其中女性通过将手靠在手上向桡骨施加力。我们使用尸体实验来描述施加在桡骨上的应变环境，并进行了一项前瞻性研究，其中 19 名成年女性每天加载其远端桡骨 50 次，每周 3 天，持续 28 周，另外 7 名成年女性作为对照组。在四个尸体标本中，加载导致压缩主应变为-1695±396με，桡骨向背侧和尺骨弯曲。前瞻性体内加载可对骨骼产生可测量的改善，并似乎可预防与体力活动和阳光暴露季节性波动相关的骨质流失。实验组的骨体积（BV）和转动惯量显著增加，而对照组的 BMC 和转动惯量则显著减少。因此，该加载模型适合作为探索人类骨骼适应性的模型系统，并且最终可能对增强女性桡骨具有临床意义。
